1. Field of the Invention
This invention relates to a recording medium, such as an optical disk, for recording data items of different classifications used for different purposes, for example, compressed moving picture data and audio data, a recording apparatus for recording data into the recording medium, are cording method for recording data into the recording medium, a reproducing apparatus for reproducing data from the recording medium, and reproducing method for reproducing data from the recording medium.
2. Description of the Related Art
Conventionally, an MPEG (Moving Picture Experts Group) system is internationally standardized as a system for compressing (coding) digital moving picture image data and audio data. The MPEG compression system is a system for subjecting digital moving picture image data and audio data to the variable-length compression.
Further, the system format system corresponding to the MPEG compression system is defined as an MPEG system layer.
The MPEG system layer is defined so as to be easily dealt with in a communication system, and transfer starting time and reproduction starting time represented by using reference time are defined for moving picture data, audio data and other data so that the above data items can be transferred and reproduced in synchronism with one another.
Further, in the MPEG system layer, the data classifications of moving picture compressed data stream (MPEG moving picture data) and audio compressed data stream (MPEG audio data) are defined by use of stream ID, and the other data classifications can be defined by the user as a private stream.
However, in this case, the user can add but two kinds of data classification, and the expandability is limited.
As a result, it becomes impossible to deal with various classifications of data items and cope with a variety of conditions in the multimedia age.
Further, if a maximum data length is set for packets of data other than MPEG audio data and if the data length of the packet cannot be divided by the number of data items of a completed frame data block, the preceding data block will enter the packet and there occurs a possibility that the starting address of the frame data block cannot be determined, and when data is reproduced halfway, it may be impossible to reproduce the data.